Every time I've seen testing on barrel lengths that they can cut up at will, they use T/C Contenders and Encores. You can (obviously) chop a barrel up but by bit and the only thing you lose besides length is a barrel. Easily and relatively cheap to replace, so it's a perfect platform for these kinds of tests.
My point? Every time anyone doing the testing snaps pictures, they are doing all the testing without a fore end. All is well.
I don't know how much difference it will make in accuracy testing, but as long as you keep an eye on the pin, I think it won't hurt at all, and I can't see it as any kind of a safety issue.